XDR is a quality-control and duplication process for the mass-production of pre-recorded audio cassettes. It is a process designed to provide higher quality audio on pre-recorded cassettes by checking the sound quality at all stages of the tape duplication process. In this way, the dynamic range of audio recorded on an XDR-duplicated cassette can be up to 13 decibel

Decibel

The decibel is a logarithmic unit that indicates the ratio of a physical quantity relative to a specified or implied reference level. A ratio in decibels is ten times the logarithm to base 10 of the ratio of two power quantities...

s greater.

History

XDR was originally developed by Capitol Records-EMI of Canada in 1982 as "SDR" (Super Dynamic Range). Capitol in the USA then adopted the system for its cassette releases that same year, renaming it "XDR".

Process

The XDR/SDR process involves many steps, the most prominent being:

• Duplication of the cassettes from a 1" wide master loop tape mounted in a loop bin duplicator
  Loop bin duplicator
  A loop bin duplicator is a specialized audio tape machine used in the duplication of pre-recorded audio cassettes.- Analog Loop Bin Duplicator :...
  
   (as opposed to standard cassette duplication using a 1/2" master loop tape), resulting in clearer high frequencies, greater bass response, and less noise.

• Recording a short test toneburst at the beginning and end of the program material on the cassette, to detect for any loss of audio frequencies in the audio spectrum
  Sound
  Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations.-Propagation of...
  
  . The toneburst consists of 11 tones about .127 seconds in length (with .023 seconds of silence in-between each tone), from 32 to 18,000 Hz. These tones are recorded on the cassette, and are read during the duplication process to detect if there is any loss of any audio information.

As well as with EMI

EMI

The EMI Group, also known as EMI Music or simply EMI, is a multinational music company headquartered in London, United Kingdom. It is the fourth-largest business group and family of record labels in the recording industry and one of the "big four" record companies. EMI Group also has a major...

 & Capitol Records, PolyGram

PolyGram

PolyGram was the name of the major label recording company started by Philips from as a holding company for its music interests in 1945. In 1999 it was sold to Seagram and merged into Universal Music Group.-Hollandsche Decca Distributie , 1929-1950:...

and other labels also offered cassette releases duplicated with the XDR process.